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Characteristics of Musical Signals

Many techniques exist for measuring audio systems with common audio test signals, such as sine waves, pulses, and noise. However, these test signals do not interact with such systems in the way music or speech do. It is interesting to make measurements on the actual signals in typical environments, and perhaps these measurements will be more relevant to the real-world behavior of the systems. Audio signals can be characterized in many general ways. Several new ways of measuring peak levels, rms levels, distributions of amplitudes, and spectra are described. The amplitude, average spectrum, peak spectrum, and the way in which the spectrum and the distribution of amplitudes change with time are all ways in which the signal can be characterized. These novel measurements can be used to detect overshoots, clipping, compression, and make a blind determination of the transfer characteristic of an ADC used to make a recording.